Mechanism of leakage current reduction of tantalum oxide capacitors by titanium doping

Lau, W. S.; Tan, Thiam Soon; Babu, P. D.; Sandler, N. P.

doi:10.1063/1.2710000

Cited by 34 publications

(19 citation statements)

References 22 publications

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“…For instance, Ta and Ti in La-Sr-Fe ͑LSF͒ oxides are interesting for catalytic oxygen membranes, 1 Ta is a hole depletion agent in photocatalysts, 2 and Ti suppresses leakage currents in high temperature tantalum capacitors. 3 The role of electron holes as charge carriers and their detection in the pre-edge of oxygen x-ray absorption spectra ͑XAS͒ has been recognized. But the pre-edges withstood quantitative treatment so far.…”

mentioning

confidence: 99%

Pre-edges in oxygen (1s) x-ray absorption spectra: A spectral indicator for electron hole depletion and transport blocking in iron perovskites

Braun

Bayraktar

Erat

et al. 2009

Applied Physics Letters

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The e g ↑ / ͑t 2g ↓ + e g ↓͒ band ratio in cation-substituted La-Fe oxides is identified in O ͑1s͒ x-ray absorption spectra as a linear spectral indicator for conducting electron holes. The t 2g ↓ and e g ↓ bands act as a conductivity inhibitor by ferromagnetic double exchange coupling on the e g ↑ electron. Disorder induced by substitution appears to modulate the hole conduction such that an exponential relation is found between the conductivity and the e g ↑ / ͑t 2g ↓ + e g ↓͒ ratio and hole concentration. The quantitative correlation of conductivity and x-ray absorption spectra from heterovalent-substituted LaFeO 3 lets substitution-driven metal insulator transitions appear in a new light.

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mentioning

confidence: 99%

Pre-edges in oxygen (1s) x-ray absorption spectra: A spectral indicator for electron hole depletion and transport blocking in iron perovskites

Braun

Bayraktar

Erat

et al. 2009

Applied Physics Letters

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“…It is also possible that other mechanisms may also exist to suppress the leakage current, as has been observed in the titanium doped tantalum oxide. Titanium doping was found to suppress the oxygen vacancies in tantalum oxide capacitors, which resulted in a significant reduction in the leakage current [38]. For the HfO 2 capacitors, there are also a considerable number of oxygen vacancies [39,40,41,42], which could potentially be suppressed when titanium is doped in the HfO 2 .…”

Section: Resultsmentioning

confidence: 99%

Electrical Properties and Interfacial Studies of HfxTi1–xO2 High Permittivity Gate Insulators Deposited on Germanium Substrates

Roberts

et al. 2015

Materials

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In this research, the hafnium titanate oxide thin films, TixHf1–xO2, with titanium contents of x = 0, 0.25, 0.9, and 1 were deposited on germanium substrates by atomic layer deposition (ALD) at 300 °C. The approximate deposition rates of 0.2 Å and 0.17 Å per cycle were obtained for titanium oxide and hafnium oxide, respectively. X-ray Photoelectron Spectroscopy (XPS) indicates the formation of GeOx and germanate at the interface. X-ray diffraction (XRD) indicates that all the thin films remain amorphous for this deposition condition. The surface roughness was analyzed using an atomic force microscope (AFM) for each sample. The electrical characterization shows very low hysteresis between ramp up and ramp down of the Capacitance-Voltage (CV) and the curves are indicative of low trap densities. A relatively large leakage current is observed and the lowest leakage current among the four samples is about 1 mA/cm2 at a bias of 0.5 V for a Ti0.9Hf0.1O2 sample. The large leakage current is partially attributed to the deterioration of the interface between Ge and TixHf1–xO2 caused by the oxidation source from HfO2. Consideration of the energy band diagrams for the different materials systems also provides a possible explanation for the observed leakage current behavior.

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“…This can be seen in Fig. 2 (4). Let us name this mechanism of I-V symmetry by suppression of defect states as Mechanism A I-V symmetry.…”

Section: Mechanism a Symmetrymentioning

confidence: 94%

A New Mechanism of Symmetry of Current-Voltage Characteristics for High-k Dielectric Capacitor Structures

Lau

2012

ECS Trans.

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Mechanism of leakage current reduction of tantalum oxide capacitors by titanium doping

Cited by 34 publications

References 22 publications

Pre-edges in oxygen (1s) x-ray absorption spectra: A spectral indicator for electron hole depletion and transport blocking in iron perovskites

Pre-edges in oxygen (1s) x-ray absorption spectra: A spectral indicator for electron hole depletion and transport blocking in iron perovskites

Electrical Properties and Interfacial Studies of HfxTi1–xO2 High Permittivity Gate Insulators Deposited on Germanium Substrates

A New Mechanism of Symmetry of Current-Voltage Characteristics for High-k Dielectric Capacitor Structures

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